Sum up a problem with AC in 200 characters or less.

[MCS]

AC needs less lag by removing the proprietary anti-cheat system,

While the anti cheat system has created many problems, its still needed as there are plenty of dynamic cheaters who can just lease a new IP and play. It should be expanded to kick ridiculous laggers, and perhaps ban players who are regular teamkillers and map vote abusers

no map restrictions so people can play the old maps again and have real fun

yes

the auto content download service needs to go,

actually that helps update clients with new material on the fly. you may know where custom material is stored, but the forum tends to have a lot of "how-to" questions, so anything to make it easier for new people to get new matertial i would think would be a plus. If you only play the same 3 maps over and over again, perhaps you don't need any new textures, sounds, map updates. You're right, a server should just kick people without the proper material; instead of letting them download it ;)

the file structure of maps and mapmodels and texture needs to be reversed back to pre-AC 1.2

I'm not sure how moving backwards helps improve the game, but perhaps the locations of things and how they interact in the program may have changed to help keep newbie cheaters at bay.